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Solaris Naming Administration Guide

Initial Context Bindings for Naming Within the Enterprise

An initial context is the starting place from which client users, hosts, and applications can (eventually) name any object in the enterprise namespace.

Figure 21-3 shows the same naming system as the one shown in Figure 21-2, except that the initial context bindings are shaded and shown in italics. These initial contexts are shown from the point of view of the user, host, or application asking for a name to be resolved.

Figure 21-3 Example of Enterprise Bindings in the Initial Context

Graphic

XFN provides an initial context function, fn_ctx_handle_from_initial(), that allows a client to obtain an initial context object as a starting point for name resolution. The initial context has a flat namespace for namespace identifiers. The bindings of these initial context identifiers are summarized in Table 21-3 and are described in more detail in subsequent sections. Not all of these names need to appear in all initial contexts. For example, when a program is invoked by the superuser, only the host and client-related bindings appears in the initial context, none of the user-related bindings appear.

Table 21-3 Initial Context Bindings for Naming Within the Enterprise

Namespace 

Identifier 

Binding 

myself, _myself, thisuser

The context of the user who is trying to resolve a name. 

myens, _myens

The enterprise root of the user who is trying to resolve a name. 

myorgunit, _myorgunit

The user's primary organizational unit context. For example, in an NIS+ environment, the primary organizational unit is the user's NIS+ home domain. 

thishost, _thishost

The context of the host that is trying to resolve a name. 

thisens, _thisens

The enterprise root of the host that is trying to resolve a name. 

thisorgunit, _thisorgunit

The host's primary organizational unit context. For example, in an NIS+ environment, the primary organizational unit is the host's NIS+ home domain 

user, _user

The context in which users in the same organizational unit as the host are named 

host, _host

The context in which hosts in the same organizational unit as the host are named 

org, orgunit, _orgunit

The root context of the organizational unit namespace in the host's enterprise. For example, in an NIS+ environment, this corresponds to the NIS+ root domain 

site, _site

The root context of the site namespace at the top organizational unit if the site namespace has been configured 

In XFN terminology, names with a leading underscore prefix are called the canonical namespace identifiers. The names without the leading underscore, with the additions of org and thisuser, are Solaris customizations. Solaris customized namespace identifiers are not guaranteed to be recognized in other, non-Solaris environments. The canonical namespace identifiers are always recognized and therefore portable to other environments.

Note -

The current implementations of FNS does not support the addition or modification of names and bindings in the initial context.

Initial context bindings fall into three basic categories:

User-related Bindings

FNS assumes that there is a user associated with a process when the XFN initial context function is invoked. This association is based on the effective user ID (euid) of the process. Although the association of user to process can change during the life of the process, the original context handle does not change.

FNS defines the following bindings in the initial context that are related to the user requesting name resolution.

myself

The namespace identifier myself (or either synonym _myself or thisuser) in the initial context resolves to the user context of whomever is making the request. For example, if a process owned by the user jsmith requests name resolution, the name:

myorgunit

FNS assumes that each user is affiliated with an organizational unit of an enterprise. A user can be affiliated with multiple organizational units, but there must be one organizational unit that is primary, perhaps by its position in the organizational namespace or by the user's role in the organization.

myens

FNS assumes that there is an association of a user to an enterprise. This corresponds to the namespace that holds myorgunit.

The namespace identifier myens (and _myens) resolves in the initial context to the enterprise root of the enterprise to which the user making the request belongs. For example, if jsmith is making the request, and jsmith's NIS+ home domain is east.sales, which in turn is in the NIS+ hierarchy with the root domain name of doc.com. The name myens/orgunit/ resolves to the top organizational unit of doc.com.

Note -

Be careful about set-user-ID programs when using user-related composite names, such as myorgunit or myself/service, because these bindings depend on the effective user ID of a process. For programs that set-user-ID to root to access system resources on behalf of the caller, it is usually a good idea to call seteuid(getuid()) before calling fn_ctx_handle_from_initial().

Host-related Bindings

A process is running on a particular host when the XFN initial context function is invoked. FNS defines the following bindings in the initial context that are related to the host the process is running on.

thishost

The namespace identifier thishost (or _thishost) is bound to the host context of the host running the process. For example, if the process is running on the machine cygnus, thishost is bound to the host context of cygnus, and the name thishost/service/calendar refers to the calendar service of the machine cygnus.

thisorgunit

FNS assumes that a host is associated with an organizational unit. A host can be associated with multiple organizational units, but there must be one that is primary. In an NIS+ namespace, this organizational unit corresponds to the host's home domain.

The namespace identifier thisorgunit (or _thisorgunit) resolves to the primary organizational unit of the host running the process. For example, if that host is the machine cygnus, and cygnus's NIS+ home domain is west.sales, then thisorgunit resolves to the organizational unit context for west.sales and the name thisorgunit/service/fax refers to the fax service of the organizational unit west.sales.

thisens

FNS assumes that there is an association of a host to an enterprise. This corresponds to the namespace that holds thisorgunit.

The namespace identifier thisens (or _thisens) resolves to the enterprise root of the host running the process. For example, under NIS+, if the host's home domain is sales.doc.com, then the name thisens/site/ resolves to the root of the site namespace of doc.com.

"Shorthand" Bindings

FNS defines the following "shorthand" bindings in the initial context to enable the use of shorter names to refer to objects in certain commonly referenced namespaces.

user

The namespace identifier user (or _user) is bound in the initial context to the username context in organizational unit of the host running the process. This allows other users in the same organizational unit to be named from this context.

From the initial context, the names user and thisorgunit/user resolve to the same context. For example, if the host running the process is a machine altair and altair is in the east.sales organizational unit, the name user/medici names the user medici in east.sales.

host

The namespace identifier host (or _host) is bound in the initial context to the hostname context organizational unit of the host running the process. This allows other hosts in the same organizational unit to be named from this context.

From the initial context, the names host and thisorgunit/host resolve to the same context. For example, if the host running the process is a machine named sirius and it is in the east.sales organizational unit, the name host/sirius names the machine sirius in the organizational unit east.sales.

org

The namespace identifier org (or orgunit, _orgunit) is bound in the initial context to the root context of the organization of the enterprise to which the host running the process belongs.

From the initial context, the names org and thisens/orgunit resolve to the same context. For example, if the host running the process is the machine aldebaran and aldebaran is in the enterprise doc.com., the name org/east.sales names the organizational unit east.sales in doc.com.

site

The namespace identifier site (or _site) is bound in the initial context to the root of the site naming system of the top organizational unit of the enterprise to which the host running the process belongs.

From the initial context, the names site and thisens/site resolve to the same context. For example, if the host running the process is the machine aldebaran and aldebaran is in the enterprise doc.com., the name site/pine.bldg-5 names a conference room, pine in building 5 of doc.com.